I'm running on a 333 compac presario..Whenever I start the computer I can hear it starting up then it just stops responding before it boots up any information, the light on the monitor wont advance to green,therefore the monitor doesnt come on, and the floppy drive will not responed. I've tried using the boot up disk to the computer but that doesnt work because it doesnt recognize the floppy drive , I have also tried to get into cmos but it doesnt respond to that either, nothing works,.. what is the problem and what can i do,.. please help me,.. Ive been dealing with this for a few weeks now... Thanks Deb

Do you remember exactly when the problem started? If so, it'd be good to remember if you changed anything on your computer or even moved it on that day. It definitely sounds like a hardware issue. What I would do is try out each part, starting with the video card, on a known good computer. Don't know if you have another computer on hand though.

Might be a power supply problem and what you are hearing is the psu fan starting, but then the required voltages are not sequencing onward into the computer such that it is not performing its startup checks and then booting.
Voltages can be simply checked using a dc voltmeter on the rear of motherboard connecter which should not be removed. Entering the psu to check its internal fuse(s) is dangerous and should not be attempted by unqualified personnel.
Please check if any cpu leds function and/or if there are any beeps, the number of which can point to the cause of fault.
Good Luck!

I think power supply is a likely cause, too. Does the floppy drive light light and stay lit? This is a point where a weak supply often hangs up.